Long Beach , California -LRB- CNN -RRB- -- Taylor Wilson is going to create a safer source of nuclear energy , help reduce the world 's stockpile of nuclear weapons , screen container ships for weapons and power manned missions to other planets . But first ... he has to graduate high school in May .

Jack Andraka is going to bring his 3-cent screening test for pancreatic , ovarian and lung cancer to market -- an alternative to a standard $ 800 test . But Jack , 16 , has n't been to high school much lately and is n't even sure he 'll graduate .

The two teenagers with Justin Bieber style haircuts wowed the 1,400 people who attended TED2013 this week , fitting the conference 's theme : `` The Young . The Wise . The Undiscovered . '' They were among a number of youthful speakers who Time magazine 's Ruth Davis Konigsberg called `` some of the biggest showstoppers at the annual event . ''

By contrast , some of the older voices onstage struck notes that were far less hopeful . Northwestern University economist Robert Gordon declared that the era of strong economic growth in the United States is over -- as America faces the headwinds of an aging population , debt , inequality and educational weaknesses ; he argued that it 's hard to foresee innovations that could have the transformative effect electricity , indoor plumbing and the internal combustion engine had in powering growth in the past century .

Former Michigan Gov. Jennifer Granholm , calling for a private sector-funded `` race to the top '' among states , lamented the inability of Washington politicians to develop a national energy strategy . She got laughs when she noted that Congress ' approval rating is worse than lice , root canals and Donald Trump -LRB- although better than that of gonorrhea and meth labs -RRB- .

TED.com : Granholm 's clean energy proposal

And Lawrence Lessig , an author and professor at Harvard Law School , sketched an even starker picture of political dysfunction , a `` pathological , democracy-destroying corruption '' in which a tiny minority of Americans representing powerful interests use their campaign donations to determine which candidates survive the primaries . Even against long odds , Lessig said the problem is fixable if enough Americans organize to bring about change .

There were other speakers whose inventiveness and ambition were unambiguously upbeat .

Jane Chen spoke about developing a lower-tech method to save the lives of premature and low birthweight babies in regions where access to incubators is n't readily available . Her social enterprise Embrace distributes a specially engineered and heated sleeping bag that provides babies the heat they ca n't generate on their own until they 're developed enough to survive .

Google CEO Sergey Brin demonstrated Google Glass , a smartphone-like piece of headgear that enables access to your contacts , your e-mail , your searches and your photos . His pitch for the device -- now being tested by a select few for $ 1,500 apiece and due on the market later this year -- is partly that it frees people up from the `` nervous habit '' of constantly checking their smartphone as they walk : `` Is this what you 're meant to do with your body ? ''

TED.com : Amanda Palmer -- the art of asking

David Lang , talked of his Open ROV project , which markets an $ 800 kit -- using off-the-shelf parts -- for a remotely operated underwater vehicle that gives its makers the ability to explore underwater worlds in James Cameron fashion .

PayPal co-founder Elon Musk did n't mention his recent dispute with a New York Times reporter over the battery range of the all-electric Tesla Model S , but made a case for the car 's virtues before describing his effort to market solar panels to homeowners and businesses and his SpaceX commercial venture to the heavens . He screened a video of a reusable 12-story-tall rocket launching , hovering and then returning to a launchpad ready for another flight .

SpaceX capsule reaches International Space Station

Keller Rinaudo demoed Romo , a $ 150 iPhone-powered robot that recently launched . It uses the brains of the phone 's computer chip , its camera and a plastic chassis with tank-style treads to zip around a room , express emotions , interact with owners , kids and pets , and function as `` Skype on wheels '' for grandparents dropping in for a virtual visit .

Edith Widder , part of the three-person team that developed the device that lured a giant squid to an underwater camera , explained how it was able to get the first-ever video displaying the enormous size and intricacy of the animal in the deep ocean .

13-year old invents system to protect family livestock from lions

Ron Finley , an activist in South Central Los Angeles , is leading an effort to counter the neighborhood 's `` food desert , '' by growing fruits and vegetables on city owned and private land . `` If kids grow kale , they 'll eat kale , '' he said . `` If kids grow tomatoes , they 'll eat tomatoes . ''

Renowned photographer SebastiÃ # o Salgado showed finely etched works from his forthcoming book `` Genesis , '' a 50-pound , $ 3,000 behemoth -LRB- there 's a less elegant and smaller version for under $ 70 -RRB- that does justice to the detail of his exquisitely composed black and white photos shot around the world .

TED.com : Sugata Mitra -- build a school in the cloud

Stewart Brand , the 78-year-old technologist who came to fame as editor of `` The Whole Earth Catalog , '' introduced an ambitious plan to recreate extinct species , using DNA from museum specimens . The effort , echoing `` Jurassic Park '' , wo n't bring back dinosaurs -- their DNA did n't survive the tens of millions of years since they disappeared -- but aims to `` de-extinct '' such species as the passenger pigeon , declared extinct in 1914 .

TED normally attracts an audience of the elite of Silicon Valley , Hollywood and venture capital , along with foundation and corporate CEOs , who pay $ 7,500 for the five-day event , which is moving next year from Long Beach to Vancouver . -LRB- CNN has a partnership with TED in which it publishes selected TED Talks along with text pieces by speakers -RRB- .

TED stands for `` technology , entertainment and design , '' although its subject matter has branched out widely since its founding nearly 30 years ago .

The ingenuity of this year 's youthful speakers was remarkable , and so was the confident way they expressed their ideas . Wilson , 18 , is finishing high school while also attending the University of Nevada at Reno . He first attracted attention for creating a nuclear fusion reactor at 14 .

In his TED Talk , he argued for an alternative to the most widely used nuclear power technologies .

Rather than create electricity by heating water and turning a turbine , Wilson 's new reactor would use nuclear fission to produce energy from molten salt . His plan would be to centrally manufacture small fission reactors and distribute them widely for burial underground . He said they could last for 30 years without refueling , compared with 18 months for larger commercial reactors .

Since the reactors would not be pressurized , radioactivity would not be expelled as widely into the environment as in an accident like the Fukushima disaster , Wilson said . Costs would be lower since reactors would not have to be built onsite . Nuclear weapons could be recycled in the reactor , he said . And most exciting to the young space geek , such a reactor could power a spaceship to a distant planet and then be the power source for a human base at the destination , he said .

Andraka , who 's 16 and a high school sophomore , won the top prize in the Intel Science Fair competition for his cancer screening test , which relies in part on carbon nanotubes to detect a protein that is present in the blood and urine in the early stages of the three deadly cancers , providing hope that they can be detected in time for a successful cure .

He told CNN in an interview that he does n't go to high school much anymore but is busy with other projects -- including inventing an MRI the size of a credit card and leading a team of high school students competing for the $ 10 million Tricorder X Prize to design a handheld device people could use to monitor their health .

Andraka and Wilson probably do n't have to worry about it but another speaker added a sobering element to the celebration of youth at TED . Meg Jay , a psychologist and author , argued against the idea that the 20s are a period of extended adolescence where people can postpone key life choices . By the time people reach 30 , they may have missed out on some key chances to take their life in the directions they hope to pursue . `` Thirty is not the new twenty , '' she said , urging people to `` claim your adulthood '' and start making choices .

Spoken word poet Shane Koyczan , a 36-year-old whose new video `` To This Day '' has attracted 5.5 million views , offered a reminder that for all that young people can achieve , many still carry a heavy burden . He told of being bullied as a child to the point that , without realizing it , he turned into a bully himself . He spoke of kids being called names , making them feel like `` oddities juggling depression and loneliness '' and challenged them :

`` if you ca n't see anything beautiful about yourself

get a better mirror

look a little closer

stare a little longer

because there 's something inside you

that made you keep trying

despite everyone who told you to quit ''

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TED2013 conference theme was `` The Young . The Wise . The Undiscovered ''

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Speakers included a mix of young and older voices , many with ambitious ideas

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One 18-year-old with nuclear reactor experience proposed a different power plant design

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Older voices expressed concern about economic and political challenges facing America